lst=input().split()
lst=list(map(lambda i:float(i),lst))
x_1=lst[0]
x_2=lst[1]
y_1=lst[2]
y_2=lst[3]
dis=((x_1-y_1)**2+(x_2-y_2)**2)**(1/2)
print(dis)

 lst=input().split() lst input().split() ().split () input split lst=list(map(lambda i:float(i),lst)) lst list(map(lambda i:float(i),lst)) list map(lambda i:float(i),lst) map lambda i:float(i) float(i) float i i lst x_1=lst[0] x_1 lst[0] lst 0 x_2=lst[1] x_2 lst[1] lst 1 y_1=lst[2] y_1 lst[2] lst 2 y_2=lst[3] y_2 lst[3] lst 3 dis=((x_1-y_1)**2+(x_2-y_2)**2)**(1/2) dis ((x_1-y_1)**2+(x_2-y_2)**2)**(1/2) (x_1-y_1)**2+(x_2-y_2)**2 (x_1-y_1)**2 x_1-y_1 x_1 y_1 2 (x_2-y_2)**2 x_2-y_2 x_2 y_2 2 1/2 1 2 print(dis) print dis y_1=lst[2] lst[2] y_1 lst=input().split() input().split() lst x_2=lst[1] lst[1] x_2 y_2=lst[3] lst[3] y_2 lst=list(map(lambda i:float(i),lst)) list(map(lambda i:float(i),lst)) lst dis=((x_1-y_1)**2+(x_2-y_2)**2)**(1/2) ((x_1-y_1)**2+(x_2-y_2)**2)**(1/2) dis x_1=lst[0] lst[0] x_1
lst=input().split()
lst=list(map(lambda i:float(i),lst))
x_1=lst[0]
x_2=lst[1]
y_1=lst[2]
y_2=lst[3]
dis=((x_1-y_1)**2+(x_2-y_2)**2)**(1/2)
print(dis)


